Coated article with metallic finish

ABSTRACT

A coated article with metallic finish which comprises a base layer of a paint containing metallic powder and, if necessary, color pigment applied to the substrate and a topcoat applied to said base layer, said topcoat being formed by applying and curing a coating material composed mainly of a silyl group-containing vinyl polymer or copolymer having the main chain composed substantially of a vinyl polymer and at least one silicon atom connected to a hydrolyzable group at the terminal or side chain per molecule.

This application is a continuation application of Ser. No. 07/640,467,filed Jan. 11, 1991, now abandoned; which is a continuation of Ser. No.515,775, filed Apr. 25, 1990, now U.S. Pat. No. 4,994,327; which is acontinuation of Ser. No. 204,848, filed Jun. 10, 1988, now abandoned;which is a continuation of Ser. No. 018,744, filed Feb. 24, 1987, nowabandoned; which is a continuation of Ser. No. 618,774, filed Jun. 11,1984, now abandoned; which is a continuation of Ser. No. 384,345, filedJun. 2, 1982, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a coated article with metallic finish. Moreparticularly, it relates to a coated article with metallic finish formedby applying a priming coat containing metal powder and, if necessary, acolor pigment, to the substrate, and subsequently applying a topcoatcontaining a vinyl polymer having the main chain composed substantiallyof vinyl polymer chain and having at least one silyl group having asilicon atom connected to a hydrolyzable group at the side chain orterminal per molecule, and finally curing the coating.

2. Description of the Prior Art

Heretofore, the metallic finish of automotive bodies has beenaccomplished with a variety of paints such as nitrocellulose lacquer,modified acrylic lacquer, straight acrylic lacquer, polyurethane paint,and baking enamel. These paints, however, were not satisfactory infastness to weathering when used as a topcoat for metallic finish. Inactual use, the coated film of these paints undergoes cracking,discoloration, blistering, and peeling when exposed to intense sunlightfor a long period of time.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a top-coat containing vinylpolymer or copolymer main chains and at least one silyl group having asilicon atom connected to a hydrolyzable group at the side chain orterminal per molecule.

It is another object of this invention to provide a topcoat which isgreatly improved in outdoor weatherability and "finish feel".

It is another object of this invention to provide a topcoat which doesnot require polishing with a fine abrasive compound to make the surfacesmooth and lustrous.

According to this invention, the top coat gives a beautiful, lustrousfinish without such polishing. This leads to labor saving and materialsaving in the coating process.

DETAILED DESCRIPTION OF THE INVENTION

In this invention, the substrate is iron, aluminum, and other metals;wood and artificial woodlike materials; and thermosetting andthermoplastic moldings with priming, rust preventive treatment, orinsect-proofing treatment.

In this invention, the metallic base coat may be aminoalkyd resin,thermosetting acrylic resin, nitrocellulose lacquer, modified acryliclacquer, straight acrylic lacquer, polyurethene resin, acrylic enamelresin, or silyl group-containing vinyl resin, but is not specificallylimited to them. The paint may be of solvent type, non-aqueousdispersion type, multi-component type, powder type, slurry type, oraqueous type. The metallic powder and color pigment to be incorporatedin the base coat may be aluminum powder, copper powder, mica powder, andusual color pigment for paint. The topcoat may be incorporated withadditives such as setting agent and leveling agent.

The silyl group-containing vinyl polymer or copolymer used in thisinvention is composed of the main chain which is substantially a vinylpolymer chain and at least one, preferably, two or more silicon atomsconnected to a hydrolyzable group at the terminal or side chain permolecule. The silyl group is usually represented by the formula:##STR1## (where X is a hydrolyzable group; R₁ and R₂ are hydrogen oralkyl group, aryl group, or aralkyl group having 1 to 10 carbon atoms;and n is an integer of 1, 2, or 3.) The hydrolyzable group includeshalogens, and alkoxy, acyloxy, ketoxymate, amino, acid amide, aminoxy,mercapto, and alkenyloxy groups.

The silyl group-containing vinyl polymer or copolymer of this inventionmay be produced in various manners, but may be advantageously producedby (1) hydrosilylation reaction between a hydrosilane and a vinylpolymer or copolymer having carbon-carbon double bonds, and (2)copolymerization of a vinyl compound and a silyl compound havingpolymerizable double bonds. These processes are described in detail inthe following.

(1) the silyl group-containing vinyl polymer or copolymer of thisinvention can be readily produced by reacting a hydrosilane compoundwith a vinyl polymer or copolymer having carbon-carbon double bonds inthe presence of a catalyst based on Group VIII transition metals. Thehydrosilane used in this process has the following formula. ##STR2##(where; R₁ is hydrogen or a monovalent hydrocarbon group having 1 to 10carbon atoms selected from alkyl group, aryl group, or aralkyl group; Xis a hydrolyzable group; and n is an integer of 1, 2, or 3.)

The hydrosilane compound in this formula includes, for example,halosilanes such as methyldichlorosilane, trichlorosilane, andphenyldichlorosilane; alkoxysilanes such as methyldiethoxysilane,methyldimethoxysilane, phenyldimethoxysilane, trimethoxysilane, andtriethoxysilane; acyloxysilanes such as methyldiacetoxysilane,phenyldiacetoxysilane, and triacetoxysilane; and other silanes such asmethyldiaminoxysilane, triaminoxysilane, methyldiaminosilane,triaminosilane, bis(dimethylketoxymate)methylsilane,bis(cyclohexylketoxymate)metylsilane, methyldiisopropenoxydilane, andtriisopropenoxysilane.

The hydrosilane may be used in any amount, but preferably in an amountof 0.5 to 2 times in mole as much as the carbon-carbon double bondscontained in the vinyl polymer or copolymer. The hydrosilane may be usedin an amount more than this, but an excess is recovered as unreactedhydrosilane.

According to this invention, a halogenated silane, which is inexpensiveand highly reactive, may be readily used as the hydrosilane compound.The silyl group-containing vinyl polymer or copolymer prepared from ahalogenated silane cures rapidly at room temperature, liberatinghydrogen halide, when exposed to air. If a chlorinated silane thehydrogen chloride thus liberated in irritating and corrosive, the use ofhalogenated silane is limited. Therefore, it is desirable to convert thehalogen to a hydrolyzable functional group such as alkoxy, acyloxy,aminoxy, amino, acid amine, ketoxymate, and mercapto group as disclosedin, for example, Japanese Patent Laid-Open No. 91546/1979.

The vinyl polymer or copolymer used in the process (1) of this inventionis not specifically limited except one containing hydroxyl groups.Examples include polymer or copolymer of acrylate esters andmethacrylate esters such as methyl acrylate, methyl methacrylate, ethylacrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate,2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate; carboxylic acidssuch as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid;acid anhydrides such as maleic anhydride; epoxy compounds such asglycidylacrylate and glycidylmethacrylate; amino compounds such asdiethylaminoethylacrylate, diethylaminoethylmethacrylate, andaminoethylvinylether; amide compounds such as acrylamide,methacrylamide, diamide itaconate, α-ethyl acrylamide, crotonamide,diamide fumarate, diamide maleate, N-butoxymethylacrylamide, andN-butoxymethylmethacrylamide; and other vinyl compounds such asacrylonitrile, iminomethacrylate, styrene, α-methylstyrene, vinylchloride, vinyl acetate, and vinyl propionate. When these vinylcompounds are homopolymerized or copolymerized, allyl acrylate, allylmethacrylate, or diallyl phthalate may be copolymerized in order tointroduce the terminals or side chains of carbon-carbon double bonds forhydrosilylation in the vinyl polymer or copolymer. The quantity of suchmonomer can be determined according to the number of silyl groupsrequired in the polymer. In addition, the molecular weight may becontrolled by adding a chain transfer agent such as n-dodecylmercaptanand t-dodecylmercaptan. The polymerization of these vinyl compounds maybe accomplished with or without solvent, and where a solvent is used,inactive solvents such as ethers, hydrocarbons, and acetate esters arepreferable.

According to this invention, a catalyst of transition metal complex isrequired in the reaction of a hydrosilane compound with thecarbon-carbon double bond. A complex of platinum, rhodium, cobalt,palladium, or nickel belonging to Group VIII is preferably used. Thehydrosilylation may be accomplished at any temperature from 50° to 150°C. and the reaction will take 1 to 10 hours.

(2) According to the other process of this invention, the silylgroup-containing vinyl polymer or copolymer may be produced by radicalpolymerization of a vinyl compound with a silane compound represented bythe formula: ##STR3## (where R₁ is a monovalent hydrocarbon groupselected from alkyl group, aryl group, or aralkyl group having 1 to 10carbon atoms; R₃ is an organic residue having a polymerizable doublebond; X is a hydrolyzable group; and n is an integer of 1, 2, or 3.)

The silane compound used in this invention includes, for example:##STR4##

These silane compounds may be synthesized in various ways. For example,they may be prepared by reacting acetylene, allyl acrylate, allylmethacrylate, or diallyl phthalate with methyldimethoxysilane,methyldichlorosilane, trimethoxysilane, or trichlorosilane in thepresence of a catalyst based on Group VIII transition metals.

Those vinyl compounds used for the synthesis of the vinyl homopolymer orcopolymer in process (1) may also be used in this process (2). Inaddition to them, vinyl compounds containing a hydroxyl group may alsobe used. Examples of such vinyl compounds include 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,2-hydroxypropyl methacrylate, 2-hydrovinyl ether, N-methylolacrylate,and ARONIX 5700 (product of Toa Gosei Co., Ltd.).

These vinyl compounds and silane compounds may be copolymerized by theconventional solution polymerization at 50° to 150° C. with a radicalinitiator and a chain transfer agent such as n-dodecylmercaptan andt-dodecylmercaptan for control of molecular weight, with or withoutsolvent. Where a solvent is used, an inactive solvent such as ethers,hydrocarbons, and acetate esters are preferable.

The silyl group-containing vinyl polymer or copolymer thus obtained issuch that the hydrolyzable group therein can be converted in the way asdisclosed in Japanese Patent Laid-Open No. 91546/1979.

In the way mentioned above, the silyl group-containing vinyl polymer orcopolymer having the main chain composed substantially of vinyl polymerchain and having at least one silyl group having a silicon atomconnected to a hydrolyzable group at the side chain or terminal permolecule can be produced.

The silyl group-containing vinyl polymer or copolymer is notspecifically limited in molecular weight. But it should preferably havea molecular weight of 1,000 to 30,000, more preferably 2,000 to 10,000,from the standpoint of storage stability and properties of cured topcoatfilm. The low molecular weight like this is preferred because theresultant paint is low in viscosity and requires less solvent. Thisleads to material saving.

The silyl group-containing vinyl polymer or copolymer is improved in potlife and adhesion of coated film, if it is incorporated with theabove-mentioned vinyl unsaturated compound containing carboxyl group,hydroxyl group, amino group, or amide group.

According to this invention, the curing of the topcoat after applicationmay be performed with or without a curing accelerator depending onconditions. Where rapid curing at a comparatively low temperature isrequired, as in automobile repair, it is advantageous to use a curingcatalyst as enumerated below.

Metal salt of carboxylic acid such as alkyl titanate, stannous octoate,dibutyltin dilaurate, and lead octoate; sulfide or mercaptide typeorganotin compounds such as monobutyltin sulfide and dioctyltinmercaptide; acid catalyst such as p-toluenesulfonic acid and phthalicacid; amines such as triethylenediaminde andN-β-aminoethyl-γ-aminopropyltrimethoxysilane; and alkali catalyst suchas sodium hydroxide. These curing catalysts should be used preferably inan amount of 0.001 to 10 wt % based on 100 wt % of the polymer.

The curing catalysts are not limited to those enumerated above, but thefollowing organotin compounds may be used.

Carboxylic acid type organotin compounds:

    (n-C.sub.4 H.sub.9).sub.2 Sn(OCOC.sub.11 H.sub.23 -n).sub.2

    (n-C.sub.4 H.sub.9).sub.2 Sn(OCOCH═CHCOOCH.sub.3).sub.2

    (n-C.sub.4 H.sub.9).sub.2 Sn(OCOCH═CHCOOC.sub.4 H.sub.9 -n).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(OCCC.sub.11 H.sub.22 -n).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(OCOCH═CHCOOCH.sub.3).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(OCOCH═CHCOOC.sub.4 H.sub.9 -n).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(OCOCH═CHCOOC.sub.8 H.sub.17 -iso).sub.2

    Sn(OCOC.sub.8 H.sub.17 -n).sub.2

Mercaptide type organotin compounds:

    (n-C.sub.4 H.sub.9).sub.2 Sn(SCH.sub.2 COO)

    (n-C.sub.4 H.sub.9).sub.2 Sn(SCH.sub.2 COOC.sub.8 H.sub.17 -iso).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 COO)

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 CH.sub.2 COO)

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 COOCH.sub.2 CH.sub.2 OCOH.sub.2 S)

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 COOCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 OCOH.sub.2 S)

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 COOC.sub.8 H.sub.17 -iso).sub.2

    (n-C.sub.8 H.sub.17).sub.2 Sn(SCH.sub.2 COOC.sub.12 H.sub.25 -n).sub.2 ##STR5##

Sulfide type oroganotin compounds: ##STR6##

Organiitin oxides:

    (n-C.sub.4 H.sub.9).sub.2 SnO

    (n-C.sub.8 H.sub.17).sub.2 SnO

Reaction products of an organotin oxide and an ester such as ethylsilicate, ethyl silicate 40, dimethyl maleate, diethyl maleate, dioctylmaleate, dimethyl phthalate, diethyl phthalate, and dioctyl phthalate.

In this invention, a solvent may be used, if necessary, in addition tothe above-mentioned components. Any solvent which solubilizes both thesilyl group-containing vinyl polymer or copolymer and the curingcatalyst, or which is miscible with them and does not causeprecipitation may be used. Examples of such solvents are aliphatichydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols,ketones, esters, ethers, alcohol esters, ketone alcohols, etheralcohols, ketone ethers, ketone esters, and ester ethers which arecommonly used for paints and coatings. If these solvents contain analkyl alcohol and/or hydrolyzable ester, the one-component compositionof this invention is further improved in stability. The alkyl alcoholhaving 1 to 10 carbon atoms is preferably used. Examples of such alkylalcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol,isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol,tertbutyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octylalcohol, and cellosolve. Examples of hydrolyzable esters includetrialkyl orthoformate such as trimethyl orthoformate, triethylorthoformate, tripropyl orthoformate, and tributyl orthoformate; andtetraalkyl orthosilicate such as tetramethyl orthosilicte, tetraethylorthosilicate, tetrapropyl orthosilicate, and terabutyl orthosilicateethyl silicate 40; and hydrolyzable organic silicon compounds of theformula: R_(4-n) SiX_(n) wherein X is a hyrdolyzable group, R is amonovalent organic group optionally containing a functional group, and nis an integer of 1-4, preferably 3 or 4, such as methyltrimethoxysilane,methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane,vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane,γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane,-aminopropyltrimethoxysilane etc., and partial hydrolyzates thereof. Thequantity of the solvent to be used varies depending on the molecularweight or composition of the silyl-group containing vinyl polymer orcopolymer, but it is determined according to the solid concentration orconsistency required in actual use.

The paint of this invention may be further incorporated with a silanecoupling agent or a reaction product thereof which contains at least onesilicon atoms connected to a hydrolyzable group per molecule, wherebythe adhesion of coated film can be improved.

The silyl group-containing vinyl polymer of this invention having themain chain composed substantially of vinyl polymer chain and having atleast one silyl group having a silicon atom connected to a hydrolyzablegroup at the side chain or terminal per molecule cures on baking at hightemperatures without curing catalyst. However, the use of a curingcatalyst is effective in the case where it is necessary to cure thepaint at room temperature or comparatively low temperatures with forceddrying as in automobile repair. This curing catalyst may be added to thesilyl group-containing vinyl polymer or copolymer, with or withoutsolvent or diluent, to prepare one-package formulations. This is veryadvantageous in workability. The one-package formulation is particularlypreferred in the case of urethane resin paint which, despite its goodsurface finish and weathering resistance, has a disadvantage that thecuring catalyst and solvent (or diluent) have to be metered and mixedprior to application. Such a two-package paint is inferior inworkability to a one-package paint. Thus, there has long been a strongdemand for a one-package paint which is free of toxicity and yetsuperior in the film performance such as finish and weatherability.

Making the paint one-package type may be accomplished by properlyselecting the silyl group-containing vinyl polymer or copolymer, acuring catalyst, and, if necessary, a solvent. The kind of eachcomponent and their composition are not specifically limited. Thetopcoat of this invention is superior in weatherability to conventionalones, but it may be incorporated with additives such as UV absorber andantioxidant. The UV absorber used in this invention is not specificallylimited, but those which are in general use may be used. Examples arebenzophenones such as 2-hydroxy-4-methoxybenzophenone,2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone,and 2,4-dihydroxybenzophenone resorcinol monobenzoate; benzotriazolessuch as 2(2'-hydroxy-5-methylphenyl)benzotriazole, and Tinuvin P,Tinuvin 320, Tinuvin 326, Tinuvin 327, and Tinuvin 328 (products ofCiba-Geigy Corp.); acrylates such as 2-ethylhexyl-2-cyano-3,3-diphenylacrylate and ethyl-2-cyano-3,3-diphenyl acrylate; salicylates such asphenyl salicylate, 4-t-butylphenyl salicylate, and p-octylphenylsalicylate; and Ni compounds such as Ni-bisoctylphenyl sulfide and[2,2'-bisthio(4-t-octylphenolate)]-n-butylamine Ni. The Ni UV absorbermay be limited in its application because some of them are colored.

The paint of this invention may be improved further in weatherability ofincorporating therein an antioxidant which is in general use in the art.Examples of such antioxidants are phenols such as2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol),4,4'-thiobis(3-methyl-6-t-butylphenol),2,2'thiobis(4-methyl-6-t-butylphenol),1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, and1,3,5-tri(2-methyl-4-hydroxy-5-t-butylphenol)butane; hindered phenolssuch as IRGANOX 1010 and IRGANOX 1076 (products of Ciba-Giegy Corp.);sulfides such as dilaurylthiodipropionate and distearylthiodipropionate;and phosphites such as tridecyl phosphite, diphenyldecyl phosphite,triphenylphosphite, and trinonylphenyl phosphite.

The coating composition used in this invention cures, forming a networkstructure, when exposed to the atmosphere at room temperature.

The paint of this invention may be applied in the conventional mannerincluding spray coating, electrostatic coating, and brush coating.

The invention will be described in detail with reference to thefollowing examples.

I. Preparation of Topcoat Paints Example 1

The following components were charged into a reactor and reacted at 120°C. for 10 hours:

    ______________________________________                                        Styrene                 700 g                                                 Butyl acrylate          400 g                                                 Methylmethacrylate      700 g                                                 γ-methacryloxypropyltrimethoxysilane                                                            500 g                                                 Azobisisobutyronitrile  100 g                                                 Toluene                 500 g                                                 Butyl acetate           500 g                                                 ______________________________________                                    

whereby a copolymer of styrene-butyl acrylate-methylmethacrylateγ-methacryloxypropyltrimethoxysilane was prepared.

According to GPC analysis, this polymer was found to have a molecularweight of 8,000, and according to the analysis of residual monomer, theconversion in polymerization was 97.5%.

Example 2

The following components were charged into a reactor and reacted at 100°C. for 10 hours:

    ______________________________________                                        Styrene                 300 g                                                 Butyl methacrylate      1,500 g                                               Acrylamide              80 g                                                  γ-methacryloxypropyltrimethoxysilane                                                            300 g                                                 Azobisisobutyrovaleronitrile                                                                          100 g                                                 Toluene                 500 g                                                 Butyl acetate           500 g                                                 ______________________________________                                    

whereby a copolymer styrene-butyl acrylateacrylamide-γ-methylacryloxypropyltrimethoxysilane was prepared. Themolecular weight was 6,000 (as determined by GPC method, to be repeatedhereafter), and the conversion was 97%.

Example 3

The following components were charged into a reactor and reacted at 120°C. for 10 hours:

    ______________________________________                                        Styrene                 300 g                                                 Butyl acrylate          400 g                                                 Methyl methacrylate     1,100 g                                               Maleic anhydride        20 g                                                  γ-methacryloxypropyltrimethoxysilane                                                            300 g                                                 Azobisisobutyronitrile  100 g                                                 Toluene                 500 g                                                 Butyl acetate           500 g                                                 ______________________________________                                    

whereby a silyl group-containing vinyl polymer was prepared. Themolecular weight was 8,000 and the conversion was 98%.

Example 4

The following components were charged into a reactor and reacted at 90°for 10 hours:

    ______________________________________                                        Styrene           300 g                                                       Butyl acrylate    400 g                                                       Methyl methacrylate                                                                             1,100 g                                                     Allyl methacrylate                                                                              150 g                                                       n-Dodecylmercaptan                                                                              40 g                                                        Azobisisobutyronitrile                                                                          20 g                                                        Toluene           500 g                                                       ______________________________________                                    

whereby an allyl group-containing vinyl copolymer was prepared. Theconversion was 98%. The resultant copolymer solution was incorporatedwith a solution of trimethyloxysilane 150 g and chloroplatinic acid0.005 g dissolved in 150 ml of isopropanol and reacted in a sealedreactor for 6 hours for addition of trimethoxysilane to the allyl groupon the side chain of the copolymer to yield a silyl group-containingvinyl copolymer. The molecular weight of the resulting copolymer was9,000.

II. Preparation of Coated Articles with Metallic Finish

The reaction products prepared in Examples 1 to 4 were incorporated witha curing catalyst as shown in Table 1 for 100 parts by weight of thesilyl group-containing vinyl copolymer, and then diluted with xylene sothat the solution viscosity as measured by the Ford cup method because15 seconds.

An aluminum powder-containing metallic acrylic urethane paint (Auto Vtop, silver, made by Dai Nippon Toryo Co., Ltd.) or an aluminumpowder-containing metallic acrylic lacquer (Acrylic 1000, silver, madeby Kansai Paint Co., Ltd.) was applied to mild steel plates. About 10minutes later, the viscosity-adjusted solutions of the silylgroup-containing vinyl copolymers prepared in Examples 1 to 4 were spraycoated as a topcoat.

For comparison, a mild steel plate was coated with a metallic acrylicurethane paint (Auto V top, silver), and about 10 minutes later, anacrylic urethane topcoat (Auto V Top, clear, made by Dai Nippon ToryoCo., Ltd.) was spray coated. (Comparative Example 1). In the same way, amild steel plate was coated with a metallic acrylic urethane paint (AutoV top, silver) and then a clear acrylic lacquer (Acryl 1000, clear) wasspray coated. (Comparative Example 2).

The coated specimens were cured at 60° C. for 40 minutes. One weeklater, the coating film was subjected to pencil hardness test, surfacegloss measurement, gasoline resistance test, thinner resistance test,yellowing resistance test, and accelerated weathering test withirradiation for 2,000 hours using a sunshine weather-O-meter. Theresults are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                                            Comparative                                                                          Comparative                                Example 1                                                                            Example 2                                                                            Example 3                                                                            Example 4                                                                            Example 1                                                                            Example 2                      __________________________________________________________________________    Metallic base                                                                             Acrylic                                                                              Acrylic                                                                              Acrylic                                                                              Acrylic                                                                              Acrylic                                                                              Acrylic                                    urethane                                                                             urethane                                                                             urethane                                                                             lacquer                                                                              urethane                                                                             urethane                       Topcoat     (Example 1)                                                                          (Example 2)                                                                          (Example 3)                                                                          (Example 4)                                                                          Acrylic                                                                              Acrylic                                                                urethane                                                                             lacquer                                                                (clear)                                                                              (clear)                        Pencil hardness                                                                           2H     2H     2H     2H     2H     HB                             Surface gloss (%)                                                                         94     95     94     96     94     80                             Gasoline resistance                                                                       ∘                                                                        ∘                                                                        ∘                                                                        ∘                                                                        ∘                                                                        x                              Thinner resistance                                                                        ∘                                                                        ∘                                                                        ∘                                                                        ∘                                                                        ∘                                                                        x                              Yellowing resistance                                                                      4.3    3.4    4.5    4.6    8.4                                   Weathering resistance                                                                     90     98     93     95     50     5                              (Retention (%) of gloss)                                                      __________________________________________________________________________

Notes to Table 1

1) Curing catalysts for the topcoats.

Curing catalysts were added as follows prior to application for 100parts by weight of the silyl group-containing vinyl copolymer.

In Example 1, 1 part by weight of dioctyltin carboxylate. In Example 2,1 part by weight of dioctyltin carboxylate. In Example 3, 1 part byweight of dioctyltin carboxylate and 2 parts by weight of dioctyltinmercaptide.

In Example 4, 1 part by weight of dioctyltin carboxylate and 2 parts byweight of dioctyltin mercaptide.

2) Pencil hardness test: In accordance with JIS S-5400.

3) Surface gloss: Determined by measuring reflectance at 60°.

4) Gasoline resistance: Determined by observing softening and hardnesschange of the film surface after immersion in regular gasoline at roomtemperature for 2 hours.

No change . . . o

Changed . . . x

5) Thinner resistance: Determined by observing the change such assoftening and blistering that takes place when 1 cc of thinner is placedon the film surface.

No change . . . o

Changed . . . x

6) Yellowing resistance: Determined by measuring, in terms of colordifference (ΔE value), the color change that takes place when thecoating film is exposed to a germicidal lamp (made by Mitsubishi DenkiCo., Ltd., Model GL-15) for 24 hours.

7) Weathering resistance: Expressed retention (%) of surface gloss interms of reflectance at 60° before and after irradiation for 2,000 hoursusing a sunshine weather-O-meter.

What is claimed is:
 1. A coated article with metallic finish whichcomprises a substrate of a member selected from the group consisting ofmetals, wood, thermosetting moldings and thermoplastic moldings, a baselayer of a paint containing metallic powder on the substrate and atopcoat on the base layer, the topcoat composed mainly of a silylgroup-containing vinyl polymer or copolymer having a main chain composedsubstantially of a vinyl polymer and at least one silicon atom connectedto a hydrolyzable group at a terminal or side chain per molecule.
 2. Acoated article as set forth in claim 1, wherein the silylgroup-containing vinyl polymer or copolymer has a molecular weight from1,000 to 30,000.
 3. A coated article as set forth in claim 1, whereinthe silyl group-containing vinyl polymer or copolymer has a molecularweight from 2,000 to 10,000.
 4. A coated article as set forth in claim1, wherein the silyl group-containing vinyl copolymer contains maleicanhydride as the copolymer component.
 5. A coated article as set forthin claim 1, wherein the silyl group-containing vinyl copolymer containsacrylamide as the copolymer component.
 6. A coated article as set forthin claim 1, wherein the hydrolyzable group connected to the silicon atomcontained in the silyl group-containing vinyl polymer or copolymer is analkoxy group.
 7. The coated article as set forth in claim 1, whereinsaid paint includes a pigment.
 8. The coated article as set forth inclaim 1, wherein said silyl group containing vinyl polymer or copolymercontains a member selected from a group consisting of styrenic monomerand methacrylic monomer.
 9. The coated article as set forth in claim 1,wherein said substrate is a member selected from the group consisting ofsteel and aluminum.
 10. A coated article with metallic finish whichcomprises a substrate of a member selected from the group consisting ofmetals, wood, thermosetting moldings and thermoplastic moldings, a baselayer of a paint containing metallic power on the substrate and atopcoat on the base layer, said topcoat composed of a one packagecoating comprising (A) a silyl group-containing vinyl polymer orcopolymer having a main chain composed substantially of a vinyl polymerand at least one silicon atoms connected to a hydrolyzable group at aterminal or side chain per molecule, (B) a curing catalyst, and (C) asolvent.
 11. A coated article as set forth in claim 10, wherein thecuring catalyst is an organotin compound of carboxylic acid type.
 12. Acoated article as set forth in claim 10, wherein the curing catalyst isan organotin compound of mercaptide type having an Sn-S bond.
 13. Acoated article as set forth in claim 10, wherein the curing catalyst isan organotin compound of sulfide type having an Sn═S bond.
 14. A coatedarticle as set forth in claim 10, wherein the solvent contains methylorthoformate.
 15. A coated article as set forth in claim 10, wherein thesolvent contains an alkyl alcohol.
 16. A coated article as set forth inclaim 10, wherein the solvent contains ethyl silicate.
 17. The coatedarticle as set forth in claim 10, wherein said paint includes a pigment.18. The coated article as set forth in claim 10, wherein said silylgroup containing vinyl polymer or copolymer contains a member selectedfrom a group consisting of styrenic monomer and methacrylic monomer. 19.The coated article as set forth in claim 10, wherein said substrate isselected from the group consisting of steel and aluminum.